[llvm] [AMDGPU] Use absolute relocations when compiling for AMDPAL and Mesa3D (PR #67791)

[Nicolai Hähnle via llvm-commits]

================
@@ -2762,7 +2766,46 @@ bool AMDGPULegalizerInfo::buildPCRelGlobalAddress(Register DstReg, LLT PtrTy,
   if (PtrTy.getSizeInBits() == 32)
     B.buildExtract(DstReg, PCReg, 0);
   return true;
- }
+}
+
+// Emit a ABS32_LO / ABS32_HI relocation stub.
----------------
nhaehnle wrote:

I think Matt meant to have this as part of instruction selection which runs after legalization and register bank allocation. It's a fair question, but I agree with you that it seems plausible to have all G_GLOBAL_VALUE handling in a single location.

https://github.com/llvm/llvm-project/pull/67791